1. Field of the Invention
This disclosure relates generally to an apparatus and method for delivering secondary fuel in the form of waste material to a kiln, and more particularly to an apparatus and method of propelling waste tires into the burner end of a cement kiln.
2. Description of the Related Art
Direct fired kilns, such as kilns used in the manufacture of cement clinker, use considerable amounts of energy, usually derived from conventional oil, gas, or coal fuels, to reach the temperatures necessary to achieve the desired results. These primary energy costs account for a large portion of the cost to produce the end product, such as cement, mortar or concrete. Because of this, industry has attempted to exploit secondary fuel sources to obtain savings in the total fuel costs and/or to reduce undesired emissions of the combustion process.
For example, it is well known in the cement industry to use waste or worn rubber tires as secondary or alternative fuel in a kiln. Cement kilns can be effectively operated using waste tires as a significant portion of the total fuel burden without adversely affecting the quality of the clinker produced. Waste tires provide a relatively inexpensive source of secondary fuel. Moreover, disposal of waste tires is increasingly becoming a major environmental issue as well as a health issue due to their role in the breeding of mosquitoes and other pests.
U.S. Pat. No. 5,564,349, entitled “Appartus for Shooting Whole Automobile Tires into a Kiln” purportedly discloses a device comprising a gun barrel, a charging device for placing automobile tires in the gun barrel, and a device for generating compressed air for propelling the automobile tire through the gun barrel. The gun barrel consists of a tube having a cross-section, which is essentially rectangular over its entire length. By designing the gun barrel with a cross-section which corresponds to the cross-section of the automobile tire, the automobile tire will fill out the entire cross-sectional area of the gun barrel thereby making it possible to provide an air pressure behind the automobile tire which is sufficient for propelling the tire through the gun barrel an into the burning zone of the kiln.
U.S. Pat. No. 5,433,573, entitled “Apparatus for Injecting Fuel into Kilns and the Like” purportedly discloses a device comprising two rubber tires rotating in opposite directions, at least one motor for rotating the tires, an entrance chute, and an exit chute. The tires rotate about horizontal and parallel axes that are in an inclined plane and spaced such that the outer radial surfaces of the tires are generally adjacent. The entrance chute has a vertical inlet portion for receiving the fuel pieces and downwardly accelerating the fuel pieces by gravity and an outlet portion open adjacent the tires for feeding the fuel pieces between the tires. The tires elastically deform around the various size fuel pieces and project them as the tires rotate. The exit chute has an axis perpendicular to the inclined plane of the tire axes for directing the projected fuel pieces through the kiln end inlet. The apparatus also includes mechanisms for making adjustments to: the inclination of projection; the windage of projection; and the spacing between the tires.
This application for patent discloses and claims an apparatus for mechanically accelerating and delivering whole waste tires into the burning zone of a kiln from the discharge end.